Catheter

ABSTRACT

A catheter which allows injection into a target region without imposing large burden on a medical patient can be provided. A catheter ( 1 ) is used by being inserted from outside of a body into a blood vessel and a distal end thereof being reached inside of a heart, that is a target region, while a proximate end thereof remaining outside of the body. The catheter ( 1 ) is configured in a way so that an injection mechanism ( 5 ) conducts injection into myocardium from inside of a heart while a forceps mechanism ( 3 ) holds myocardium inside of the heart. In the forceps mechanism ( 3 ), a grasping portion ( 13 ) provided at the distal end of the catheter ( 1 ) opens and closes in conjunction with manipulation at a first handling portion ( 11 ) provided at the proximate end of the catheter ( 1 ). In the injection mechanism ( 5 ), an injection needle ( 43 ) provided at the distal end of the catheter ( 1 ) is protruded from the distal end of the catheter ( 1 ) in conjunction with manipulation at a second handling portion ( 41 ) provided at the proximate end of the catheter ( 1 ).

TECHNICAL FIELD

The present invention relates to a catheter.

BACKGROUND ART

In recent years, vascularization wherein a blood vessel is vascularizedin an ischemic heart by injecting various kinds of injectant including avascularization factor (such as protein, genes etc.) has been conducted.By this treatment method, this treatment can be applied to some casesfor those medical patients to whom it is difficult to conductPercutaneous Transluminal Coronary Angioplastry (PTCA) or CoronaryArtery Bypass Grafting (CABG), and this treatment method has beendrawing attention as a new treatment method.

Meanwhile, in case myocardial cells become necrotized from myocardialinfarction or myocarditis, remaining myocardium increasingly enlargesand compensates for reduced cardiac function. However, if thiscompensation fails, myocardium is caused. Organ regeneration, whereinlost myocardial cells are regenerated by injecting embryo myocardialcells, skeletal muscle cells, smooth muscle cells, marrow cells or EScells into myocardium, has been considered. Today, certain degree ofeffect in animal experiments, mainly in cell transplants, has beenreported. It seems regeneration of myocardium might be possible in thefuture by gene introduction. Moreover, treatment which can be adaptablefor dilated cardiomyopathy and minimally invasive to patients with noother treatment than heart transplants is expected. Additionally, itseems this kind of organ regeneration is going to be widely consideredfor other diseases, as well as for heart diseases.

Furthermore, as treatment for bradyarrhythmia, instead of implanting apacemaker, generation of spontaneous pulsation of myocardium (abiological pacemaker) has been attempted. For this treatment, injectionof various kinds of injectant (for example, cell transplants, geneintroduction, or administration of some kind of hormone preparation)into ventricular myocardium has been considered.

However, when the various kinds of treatment described above areconducted, injection into an organ (such as myocardium) needs to beconducted, accordingly surgical thoracotomy and direct injection intotreatment region have to be conducted. In this way, invesiveness to apatient is tremendous, and this has been a problem.

The present invention is to solve above problems, and the purpose is toprovide a catheter with capability of injection into a target regionwithout imposing enormous burden on a patient.

DISCLOSURE OF INVENTION

In order to attain the above object, a catheter of the present inventionis a catheter used by being inserted into a coelom from outside of abody, and a distal end thereof being reached to a target region while aproximate end thereof being remained outside of the body. The cathetercomprises: a forceps mechanism having a fist handling portion providedat the proximate end and a grasping portion provided at the distal end,wherein the grasping portion opens and closes in conjunction withmanipulation at the first handling portion, and wherein the graspingportion is capable of holding the target region; and an injectionmechanism having a second handling portion provided at the proximate endand an injection needle provided at the distal end, wherein theinjection needle is moved forward up to a position to be protruded fromthe distal end and is moved back up to a position to be stored inside ofthe distal end, and wherein the injection needle is capable ofpuncturing the target region to inject injectant into the target region.

In this catheter, specific configuration of detail parts of the forcepsmechanism can be any configuration, as long as the grasping portionprovided at the distal end opens and closes in conjunction withmanipulation at the first handling portion provided at the proximateend. For example, a configuration, wherein one wire is lead through incenter of a catheter and one end of the wire is connected to thegrasping portion, the grasping portion opens when pushed by the wire,and closes when pulled by the wire, in association with reciprocation ofthe wire along an axial direction created by manipulation of the firsthandling portion at the proximate end, can be possible. Alternatively, apower transmission mechanism, wherein turning of a similar wire isconverted into opening/closing movement of the grasping portion, can beconfigured.

Specific configuration of detail parts of the injection mechanism can beany configuration, as long as the injection needle provided at thedistal end moves forward up to a position to be protruded from thedistal end and moves back up to a position to be stored inside of thedistal end in conjunction with manipulation at the second handlingportion provided at the proximate end, and the injection needlepunctures a target region to allow injectant injected into the targetregion. For example, following configuration can be possible: one tubeis lead through in center of a catheter and one end of the tube isconnected with the injection needle. When the tube is reciprocated alongwith an axial direction by manipulating the second handling portionprovided at the proximate end, the injection needle is reciprocatedtogether with the tube. The injection needle is protruded from thedistal end while moving forward, and is stored inside of the distal endwhile moving back. In this case, a lumen of the tube can be used as aninjectant supply path to supply injectant to the injection needle.Alternatively, a wire can be disposed in parallel to the tube for movingthe injection needle forward/backward in association with reciprocatemovement of the wire, so that the tube can be used only as an injectantsupply path. In case this kind of tube is provided, a syringe can beconnected to the tube at the proximate end of the catheter, andinjectant is injected by using the syringe. Accordingly the injectantcan be supplied to the injection needle through the tube. In order tosupply injectant, a tube described above does not have to be used. Asupplier can be configured, for example, to have a injectant storageformed at the distal end of the catheter, and when pressure is appliedto the injectant storage corresponding to manipulation at the proximateend of the catheter, injectant is released from the injectant storageand supplied to the injection needle.

As for injectant, any injectant can be used, as long as the injectantcan be injected through the injection needle and suitable for atreatment target. However, since some types of medicine, genes, proteinand cells are considered for vascularization and organ regeneration, useof these kinds of injectant can be possible.

It should be noted that other than the above-described forceps mechanismand the injection mechanism, a configuration that other catheters forinserting into coelom have can be used together. For example, if a guidewire is used for inserting the catheter into coelom, a tube thatprovides a lumen to lead through the guide wire can be disposed inparallel to the above-described forceps mechanism and the injectionmechanism. Alternatively, a lumen for measuring blood pressure, or alumen for securing bloodstream, that derives blood introduced from oneend thereof to another end, can be provided. Moreover, a reinforcementmember or covering member in order to improve strength and slipperinessof the catheter can be also voluntarily used within a scope not toprevent main function of the present catheter in consideration of placewhere this catheter is used.

In usage of a catheter configured as above, first the catheter isinserted into coelom from outside of a body, and while the proximate endis remained outside of the body, the distal end is reached to a targetregion. As for methods to insert the catheter into coelom and to reachthe distal end to a target region, same methods can be voluntarily usedas methods used for various catheters for inserting coelom. When thedistal end is pushed toward the target region, the injection needle ofthe injection mechanism should be moved back, in advance, up to aposition to be stored inside of the distal end of the catheter. Thereby,puncture of the injection needle into an unexpected part can beprevented.

Once the distal end of the catheter is reached to the target region, thetarget region is held with the grasping portion of the forcepsmechanism. Thereby, even the target region moves, displacement of thedistal end of the catheter in relation with the target region can beprevented. When the relational position of the distal end of thecatheter and the target region is fixed by the forceps mechanism, theinjection needle of the injection mechanism is moved forward to puncturethe target region, and injection into the target region is conducted. Atthis time, if injectant has high consistency, or if relatively largeamount of injectant needs to be injected into one spot, force toward adirection to push back the injection needle is applied to the injectionneedle corresponding to injection of injectant. However, in thiscatheter, since the grasping portion of the forceps mechanism is holdingthe target region, the injection needle does not get pushed back orpulled out, and high stability during injection can be maintained.

After conducting injection with above-described procedure, the catheteris removed in same manner as various catheters, that are inserted intocoelom, are removed.

With a catheter described above, injection into a target region can beconducted by using the catheter. Moreover, appropriate injection can beconducted while preventing displacement of the distal end of thecatheter in relation with the target region, especially even if thetarget region moves.

For more specific example, this catheter can preferably conductinjection into myocardium. That is, displacement of the distal end ofthe catheter in relation with inner surface of a heart can be preventedby inserting the catheter into a blood vessel, reaching the distal endto inside of the heart, and holding the inner surface of the heart withthe grasping portion of the above-described forceps mechanism. Injectioncan be conducted into myocardium from inside of the heart with theinjection mechanism. Specially, since the grasping portion of theforceps mechanism can hold inner surface of a heart, injection intomyocardium can be easily and appropriately conducted without the distalend of the catheter displaced in relation with inner surface of a heart,even the heart pulsates.

Therefore, for conducting vascularization, organ regeneration, ortreatment with a biological pacemaker, injection into a treatment regionsuch as myocardium can be conducted without surgical thoracotomy, andburden imposed on a patient can be reduced.

The catheter described above becomes more preferable with followingconfiguration.

The forceps mechanism can be configured to bias the grasping portiontoward a direction to close the grasping portion with force of a spring.

In a catheter configured as above, once the grasping portion of theforceps mechanism is opened, the grasping portion can be closed with theforce of the spring. Thus, it is not necessary to apply external forceto close the grasping portion, and the grasping portion can be easilyclosed. Moreover, since closed state of the grasping portion can bemaintained with the force of the spring, it is easier to keep thegrasping portion closed, compared to a configuration wherein externalforce needs to be continuously applied in order to keep the closedstate.

Furthermore, the forceps mechanism may be provided with a lock devicethat forbids the grasping portion opening/closing.

In a catheter configured as above, the closed state of the graspingportion can be maintained by the lock device of the forceps mechanism.Thus, when the grasping portion holds a target region, the state of thegrasping portion can be more easily maintained, compared to aconfiguration wherein external force needs to be continuously applied inorder to keep the grasping portion closed.

Still furthermore, the injection mechanism may be configured to bias theinjection needle toward a direction to move back the injection needlewith the force of a spring.

In a catheter configured as above, after being moved forward, theinjection needle can be moved back with the force of the spring andstored inside the catheter. Thus, it is not necessary to apply externalforce to move back the injection needle, and the injection needle can beeasily moved back. Moreover, since state, wherein the injection needleis moved back, can be maintained with the force of the spring, theinjection needle can be maintained more easily in the retreated state,compared to a configuration wherein external force needs to becontinuously applied in order to maintain the retreated state.

Still furthermore, the injection mechanism may be provided with a lockdevice that forbids the injection needle moving back.

In a catheter configured as above, state, wherein the injection needleis moved forward, can be maintained with the lock device of theinjection mechanism. Thus, it is easier to maintain the advanced stateof the injection needle, compared to a configuration wherein externalforce needs to be continuously applied in order to maintain the advancedstate, and the injection needle does not get pulled out of a targetregion by being accidentally moved back. Moreover, since the retreatedstate of the injection needle can be maintained by the lock device ofthe injection mechanism, it is easier to maintain the retreated state ofthe injection needle, compared to a configuration wherein external forceneeds to be continuously applied in order to keep the retreated state.Thus, accidental puncture of the injection needle into an unexpectedbody part can be prevented.

In addition to above-described configurations, a configuration, whereina third handling portion is provided at the proximate end, and thedistal end is curved in conjunction with manipulation at the thirdhandling portion, can be possible.

In a catheter configured as above, since a position of the distal endcan be adjusted by curving the distal end, and a puncture position ofthe injection needle can be more accurately controlled.

Moreover, for position adjustment of the distal end, a position of thedistal end of the catheter of the present invention can be adjusted byintroducing a guide catheter having a configuration capable ofcontrolling direction of a leading end into coelom, introducing thecatheter of the present invention into a lumen of this guide catheter,and manipulating the guide catheter.

BRIEF DESCRIPTION OF DRAWINGS

FIGS. 1A to 1C are schematic diagrams of a catheter described in anembodiment of the present invention;

FIGS. 2A and 2B are sectional views showing details of a forcepsmechanism; and

FIGS. 3A and 3B are sectional views showing details of an injectionmechanism.

BEST MODE FOR CARRYING OUT THE INVENTION

Preferred embodiments of the present invention will now be describedwith some examples.

FIGS. 1A to 1C are schematic diagrams of a catheter 1 shown as anembodiment of the present invention.

This catheter 1 is used by being inserted into a blood vessel fromoutside of a body, and a distal end thereof being reached to a targetregion, i.e. inside of a heart, while a proximal end thereof beingremained outside of the body. The catheter 1 is configured to conductinjection into myocardium with an injection mechanism 5, while holdingthe myocardium with a forceps mechanism 3 from inside of the heart.

In the forceps mechanism 3, a grasping portion 13, provided at thedistal end of the catheter 1, opens and closes in conjunction withmanipulation with a first handling portion 11 provided at the proximateend of the catheter 1.

More specifically, the first handling portion 11 comprises a cylinder15, a piston 17, and a spring 19. When external force is applied, thepiston 17 can be pushed into the cylinder 15. When external force isrelieved, the piston 17 is returned to an original position by force ofthe spring 19. In a vicinity of the grasping portion 13, as shown inFIGS. 2A and 2B, an outer tube 21, a first inner tube 23, a rod 25, aslider 27, a link 29, a spring 31, and stopper 33 are provided. One endof a wire 35 led through inside of the catheter 1 is connected to theabove-mentioned rod 25, and another end of the wire 35 is connected tothe above-mentioned piston 17. On a lateral side of the cylinder 15, ascrew 37 is provided as a lock device of the forceps mechanism. Bytightening this screw 37, the piston 17 can be fixed in the cylinder 15.

In the forceps mechanism 3 with the configuration described above, whenthe piston 17 is pushed into the cylinder 15, the wire 35 iscorrespondingly pushed out toward a direction of the distal end, the rod25 is pushed by the wire 35, and the rod 25 compresses the spring 31while pressing the link 29. By restriction of the first inner tube 23,the link 29 cannot be laterally expanded. Until going outside of thefirst inner tube 23, the link 29 transfers expansion force thereof tothe slider 27 without being expanded, and the slider 27 slides toward adirection of an leading end of the forceps mechanism 3. When the link 29goes outside of the first inner tube 23, the slider 27 slides and thelink 29 expands laterally. The slider 27 is disposed in a manner so thatmovement thereof is restricted after sliding for specific amount.Consequently, the movement of the slider 27 stops after some portion ofthe slider 27 is protruded from the outer tube 21. Subsequently, thelink 29 is pushed by the rode 25 and furthermore expanded laterally, andthe grasping portion 13 opens widely.

After the grasping portion 13 is opened as described above, the forceapplied to the piston 17 is relieved, and the piston 17 is returned tothe original position by the force of the spring 19. Correspondingly,the wire 35 is pulled toward the direction of the proximate end, and atthe same time, the rod 25 is pulled by the force of the spring 31. Thelink 29 is pulled toward the direction of the proximate end by theseforces. As the laterally expanded width of the link 29 gets hung up onan end face of the outer tube 23, the width is narrowed, and the link 29is withdrawn inside of the first inner tube 23. Concurrently, the slider27 is withdrawn inside of the first inner tube 23. The grasping portion13 is closed in conjunction with this movement of the link 29.

The injection mechanism 5 is configured in a manner so that an injectionneedle 43, provided at the distal end of the catheter 1, is protrudedfrom the distal end of the catheter 1 in conjunction with manipulationat a second handling portion 41 provided at the proximate end of thecatheter 1.

More specifically, the second handling portion 41 comprises a cylinder45, a piston 47, and a spring 49, as well as the first handling portion11. When external force is applied, the piston 47 can be pushed into thecylinder 45. When the external force is relieved, the piston 47 isreturned to an original position thereof by force of the spring 49.Moreover, as shown in FIGS. 3A and 3B, in vicinity of the injectionneedle 43, the above-described outer tube 21, a second inner tube 51,and a stopper 53 are provided. One end of an injectant supply tube 57lead through inside of the catheter 1 is connected to the injectionneedle 43. Another end of the injectant supply tube 57 is introducedfrom the above-mentioned piston 47, and a syringe connecting portion 59,wherein a syringe (not shown) for injecting injectant can be connectedthereto, is formed. The injectant supply tube 57 is fixed so as not tobe displaced in relation with the above-described piston 47.Additionally, a screw 61 is provided on a lateral surface of thecylinder 45 as a lock device of the injection mechanism. By tighteningthis screw 61, the piston 47 can be fixed to the cylinder 45.

In FIGS. 3A and 3B, to avoid complication in the drawings, theabove-described forceps mechanism 3 is not illustrated. However, theouter tube 21 shown in FIGS. 3A and 3B is the same as the outer tube 21shown in FIGS. 2A and 2B. The first inner tube 23 shown in FIGS. 2A and2B and the second inner tube 51 shown in FIGS. 3A and 3B are disposed inparallel inside of the outer tube 21.

In the injection mechanism 5 with a configuration described above, whenthe piston 47 is pushed into the cylinder 45, the injectant supply tube57 is correspondingly pushed out toward the direction of the distal end.The injection needle 43 is pushed by the injectant supply tube 57, andthe injection needle 43 is protruded from the outer tube 21. Movement ofthe injection needle 43 is restricted when the injection needle 43 abutson the stopper 53. Thus, maximum protruding amount of the injectionneedle 43 becomes constant.

After the injection needle is protruded and the force applied to thepiston 47 is relieved, the piston 47 is returned to the originalposition by the force of the spring 49. Correspondingly, the injectantsupply tube 57 is pulled toward the direction of the proximate end, andthereby the injection needle 43 is pulled into inside of the secondinner tube 51.

The catheter 1 configured as above can be used according to followingprocedure.

First, the catheter 1 is inserted into a blood vessel from outside of abody. Leaving the proximate end thereof outside of the body, the distalend thereof is reached into inside of a heart. For insertion, a punctureneedle is punctured and a sheath is inserted in advance, as well as forinserting a known catheter. The catheter 1 can be introduced through alumen of the sheath. As regards a method of reaching the distal end ofthe catheter 1 into inside of a heart, a same method of a catheter, usedby reaching a leading thereof into a heart, can be voluntarily used. Forexample, a method wherein a tubular guide catheter is reached intoinside of a heart in advance and the catheter 1 is inserted along alumen of the guide catheter, or a method wherein a guide wire is reachedinto inside of a heart in advance and the catheter 1 is inserted alongthe guide wire can be voluntarily used.

When the distal end of the catheter 1 is inserted into inside of aheart, the injection needle 43 provided in the injection mechanism 5 ismoved back to a position to be stored inside of the distal end of thecatheter 1. By tightening the screw 61, the piston 47 is locked, and theinjection needle 43 does not get pushed out, even if the piston 47 istouched. Thereby, puncturing unexpected spot with the injection needle43 can be prevented.

When the distal end of the catheter 1 reaches inside of a heart,myocardium is held with the grasping portion 13 of the forceps mechanism3. When holding myocardium, the grasping portion 13 is opened and closedby manipulating the piston 17 at the first handling portion 11.Although, the piston 17 actively moves toward a closing direction by theforce of the spring 19 and the like, the piston 17 can be manuallypulled. When myocardium is held with the grasping portion 13 by theabove-described manipulation, the screw 37 is tightened to lock thepiston 17. Thereby, the holing of myocardium with the grasping portion13 does not get released even if the piston 17 is touched.

Consequently, when myocardium is held with the grasping portion 13 asabove, even the myocardium moves corresponding to pulsation, a positionof the distal end of the catheter 1 in relation with myocardium does notget displaced.

In the above state, the injection needle 43 of the injection mechanism 5is moved forward to puncture myocardium, and injection into myocardiumis conducted. When puncturing myocardium, the screw 61 is onceuntightened to release the locking of the piston 47, the piston 47 issubsequently pushed into the cylinder 45, and then the screw 61 istightened again to lock the movement of the piston 47. Thereby, fallbackand slipping out of the injection needle 43 can be prevented. In thisstate, injection into myocardium can be conducted by using a syringe(not shown) connected to the syringe connecting portion 59, andinjecting injectant. At this time, if injectant has high consistency, orif relatively large amount of injectant needs to be injected into onespot, the injection needle 43 receives force toward a direction to whichthe injection needle 43 is pushed back corresponding to injection ofinjectant. However, in this catheter 1, since the grasping portion 13 ofthe forceps mechanism 3 is holding myocardium, the injection needle 43is not pushed back or slipped out. Thus, high stability during injectioncan be maintained.

It should be noted that in the above procedure, the step of punctureinto myocardium and steps after puncture can be repeated several timesin the same manner. Thereby, injection into several parts of myocardiumcan be easily conducted.

After conducting injection, the catheter 1 is removed in a same methodas a method of various catheters which are inserted into a coelom.

With the catheter 1 described above, injection into myocardium can beconducted by using the catheter 1. Specially, even when myocardium movescorresponding to pulse of a heart, displacement of the position of thedistal end of the catheter 1 in relation with myocardium can beprevented, and injection can be appropriately conducted.

Consequently, when vascularization, wherein a blood vessel isvascularized in an ischemic heart, is conducted, injection intomyocardium can be conducted without surgical thoracotomy operation, andburden on a patient can be reduced.

Although, an embodiment of the present invention is described above, thepresent invention is not limited to a specific embodiment describedabove, and can be conducted in various forms other than the aboveembodiment.

For example, although the above embodiment does not mention, in additionto the forceps mechanism 3 and the injection mechanism 5, additionalconstituents provided in other catheters which are inserted into a bloodvessels can be also used.

Specifically, if a guide wire is used when the catheter 1 is insertedinto a blood vessel, a tube that provides a lumen to lead the guide wirecan be disposed in parallel to the above-described forceps mechanism andthe injection mechanism. A lumen for measuring blood pressure, or alumen for ensuring bloodstream to derive blood introduced from one endto another end can be provided. Alternatively, reinforcement member orcovering member in order to improve strength and slipperiness of thecatheter can be also used voluntarily within a scope not to prevent themain function of the catheter in consideration of place where thiscatheter is used.

Moreover, a third handling portion can be provided at the proximate endof the catheter 1 to make a configuration so that the distal end of thecatheter 1 is curved in association with manipulation at the thirdhandling portion and a direction of the distal end can be voluntarilychanged. With a catheter configured as above, a position of the distalend can be adjusted by curving the distal end. Thus, a puncture positionof the injection needle 43 can be more precisely controlled.

In the above embodiment, usage of the catheter 1 in vascularization isspecifically described. Usage of the above catheter 1 can be alsoapplied to organ regeneration for cardiomyopathy, or introduction ofso-called a biological pacemaker for arrhythmia. Furthermore, not onlyfor treatment intended for heart, but a catheter adopting theconfiguration of the present invention can be also used for injectioninto other parts of a body in addition to myocardium. In that case, itgoes without saying that corresponding to a target region, length andthickness of the catheter can be appropriately changed. Stillfurthermore, corresponding to strength or flexibility required to thecatheter, various kinds of resin materials used for manufacturing thistype of catheter can be used in voluntary combination.

Additionally, in the above-described embodiment, the catheter 1 isprovided with the scissors-like (beak shaped) grasping portion 13configured with two pieces of movable portions. Depending on a graspingtarget, a grasping portion can be configured with more than two movableportions that open and close radially. Furthermore, in theabove-described embodiment, some portion of the grasping portion thatcomes in contact with a grasping target is serrated. However, any shape,such as a shape with several spines protruding, can be voluntarilyadopted, as long as the contact portion can steadily hold a graspingtarget.

INDUSTRIAL APPLICABILITY

The present invention renders a catheter that allows injection into atarget region without imposing large burden to a patient. With thiscatheter, injection, for example, into myocardium while holdingmyocardium inside a heart can be conducted.

1-5. (canceled)
 6. A catheter used by being inserted from outside of abody into a coelom and reaching a distal end thereof to a target regionwhile a proximate end thereof being remained outside of the body, thecatheter comprising: a forceps mechanism having a fist handling portionat the proximate end and a grasping portion at the distal end, thegrasping portion being configured to open and close in conjunction withmanipulation at the first handling portion, and being capable of holdingthe target region; an injection mechanism having a second handlingportion at the proximate end, and an injection needle at the distal end,the injection needle being configured to be moved forward up to aposition to be protruded from the distal end, and to be moved back up toa position to be stored inside of the distal end, the injectionmechanism being capable of puncturing the target region with theinjection needle and injecting injectant into the target region, theforceps mechanism having a link mechanism configured to open and closethe grasping portion corresponding shifting of the grasping portion. 7.The catheter as set forth in claim 6, wherein the forceps mechanism isconfigured to bias the grasping portion toward a direction to close thegrasping portion with force of a spring.
 8. The catheter as set forth inclaim 6, wherein the forceps mechanism comprises a lock device thatforbids the grasping portion opening and closing.
 9. The catheter as setforth in claim 6, wherein the injection mechanism is configured to biasthe injection needle toward a direction to move back the injectionneedle with force of a spring.
 10. The catheter as set forth in claim 6,wherein the injection mechanism comprises a lock device that forbids theinjection needle moving back.